If you move weight from near the cg to near the tail and nose of the fuse, the weight of the plane does not change and if you do it a particular way the cg can remain the same. This would require moving most of the weight forward and the rest aft to maintain constant cg. What then does change is the moment of inertia about the pitch axis (and the yaw axis). Just as acceleration equals force/ mass, angular acceleration equals torque/ moment of inertia. This means for the same elevator deflection and speed, a plane with the weight far from the cg (fore and aft) will rotate in pitch more slowly than one with the weight more concentrated near the cg. The plane will be sluggish in pitch , slower to respond and slower to stop rotating.
The same applies with weight toward the wing tips. This increases the moment of inertia on the roll axis making the plane more sluggish in roll.